Answer: One of the things a trader needs to reconcile when choosing a broker is cost versus coverage, though that usually forms part of a wider discussion about how well suited a broker is to your overall needs. This means that you need to consider other factors such as minimum trade sizes/ minimum ticket charges, daily funding charges, market access and so on.
If you want deep coverage of CFDs on US equity markets then you are probably going to be looking at bigger brokers, for instance, IG offers access to more than 6500 US-listed equities and ETFs they can be traded at 2 cents per share with a minimum ticket of US$15.00 for online deals, though that rises to $25.00 for deals struck over the phone.
Where as Saxo Markets, which offers CFDs on stocks listed on four North American exchanges, basis its charges on client classification and levels of activity. Charges start at 2 cents per share with a US$10.00 minimum ticket charge, for clients with a classic account. However, that can fall to as low as 1 cent per share with just a $3.00 minimum ticket for VIP account holders ,all of these charges are for online trading.
US owned Interactive Brokers takes different approach again and its charges are based purely on volumes traded. For example if you trade 300,000, or less., US shares per month then you can expect to be charged 0.50 cents per share with a minimum ticket charge of a dollar per deal. But if you are a very active trader and turn over between 20 and 100 million US shares per month then that can fall to 0.30 cents commission with a 65 cent minimum ticket charge.
On balance Rashed you will probably do better to take a more holistic approach to broker selection and judge the whole offering in the round (rather than relying solely on costs as an indcator) including trading platforms, availability of support, plus access to research and educational resources etc. But I hope this answer has given you some pointers. If not you can compare CFD broker for trading US shares here.